Invasive weed eyes NY lakes

Ithaca and Cornell University officials are rushing to prevent the spread of Hydrilla verticillata, an invasive plant species, into Cayuga Lake.

To help stop the spread of hydrilla, the Allan H. Treman State Marine Park has been ordered to close for the season. This is so boats won’t cut through the hydrilla and risk bringing it into the rest of the lake. Ithaca Mayor Carolyn Peterson has declared an environmental emergency and asked authorities to close the inlet for the application of herbicide.

University staff discovered the aquatic tape grass for the first time in New York State waters in the mouth of Cascadilla Creek and the Cayuga Lake Inlet this August. The plant has an aggressive growth rate, up to one inch each day, for a maximum of 30 feet. that chokes waterways, crowds out native species and can lead to fish kills.

“A rapid response team has been convened to try to understand what creeks and water bodies are affected by the invasion,” Finger Lakes Institute director Lisa Cleckner said. “We all need to be mindful of the plant and other invasive species when using boats and other watercraft as well as trailers in our lakes. The propellers of the motors as well as the watercraft itself should be inspected and rinsed of all plant and animal fragments.”

Biologists worry that if hydrilla gains a toehold in Cayuga Lake, it could easily rifle through the canal system and spread into the Great Lakes, where the plant would bring drastic changes to the ecosystem.

“Hydrilla meets all of the qualifications of an invasive plant and it is considered one of the most problematic aquatic invasive species in North America” said Oswego State aquatic plant ecologist Eric Hellquist in an email.

Hydrilla’s height creates large masses of vegetation when it reaches water surfaces, blocking sunlight needed by native aquatic plants at lower depths. Waterfoul and fish that depend on diverse food webs are left in the cold. Once the plant reaches the water’s surface, it gathers in thick mats of vegetation, which could clog irrigation lines. Hydrilla can also spawn blue-green algae that decrease the amount of oxygen in water, threatening fish that need the dissolved oxygen to breath. The algae have also been shown to produce a neurological toxin that has been linked to eagle deaths, Dr. Holly Menninger said. She’s the coordinator of the New York Invasive Species Research Institute at Cornell University.

To help stop the spread of hydrilla, the Allan H. Treman State Marine Park has been ordered to close for the season. This is so boats will not cut through the hydrilla and risk bringing it into the rest of the lake. Ithaca mayor Carolyn Peterson has declared an environmental emergency and asked authorities to close the inlet for the application of herbicide.

“It’s not just recreation and tourism that will be hurt with the Hydrilla,” Menninger said. “It’s an ecological disaster in the making.”

Measures are being taken to prevent a catastrophe, but they are costly; Florida spends millions of dollars every year to maintain the spreading Hydrilla. California has been able to turn back the plants growth with application of aquatic herbicides.

Other methods are less successful. Leaf-mining flies have mimimal effectiveness, and sterile grass carp, which feast on hydrilla, could not be contained in a body the size of Cayuga Lake, Menninger said. Mechanical harvesting, where divers pull the plant out by hand, is risky, as even the smallest escaped fragment from the plant can take root and form a new colony.

That is not the plant’s only way of reproducing, either. In fall, the leaves sprout tiny buds, called turions, which release and float on the water. Anywhere they land is at risk for new colony growth. In addition, overwintering root tubers, like small potatoes can regrow a hydrilla plant.